WO2010044626A2 - Fine signal detector - Google Patents

Fine signal detector Download PDF

Info

Publication number
WO2010044626A2
WO2010044626A2 PCT/KR2009/005944 KR2009005944W WO2010044626A2 WO 2010044626 A2 WO2010044626 A2 WO 2010044626A2 KR 2009005944 W KR2009005944 W KR 2009005944W WO 2010044626 A2 WO2010044626 A2 WO 2010044626A2
Authority
WO
WIPO (PCT)
Prior art keywords
signal
frequency
reference signal
synthesized
component
Prior art date
Application number
PCT/KR2009/005944
Other languages
French (fr)
Korean (ko)
Other versions
WO2010044626A3 (en
Inventor
최영완
김두근
정인일
Original Assignee
중앙대학교 산학협력단
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 중앙대학교 산학협력단 filed Critical 중앙대학교 산학협력단
Publication of WO2010044626A2 publication Critical patent/WO2010044626A2/en
Publication of WO2010044626A3 publication Critical patent/WO2010044626A3/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/10—Means associated with receiver for limiting or suppressing noise or interference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
    • H04B1/06—Receivers
    • H04B1/16—Circuits
    • H04B1/30—Circuits for homodyne or synchrodyne receivers

Definitions

  • the present invention relates to an apparatus for detecting a fine signal, and more particularly, to an apparatus for detecting a desired signal from a signal containing a relatively large level of noise.
  • Noise affecting the detection of fine signals is noise generated on the signal line by inductive coupling or capacitive coupling, noise mixed into the power supply, noise caused by a difference in ground potential or current flowing through the ground, noise generated inside the amplifier, and a signal. Originally included noise or noise generated by the sensor itself.
  • a lock-in amplifier is used to detect a fine signal without being affected by such noise.
  • a lock-in amplifier is a detector that recovers a signal that is partially or completely buried in noise. It is often used when there is much louder noise than the signal to actually detect.
  • the lock-in amplifier may extract a magnitude component of the detection target signal by multiplying the wideband detection target signal by using a specific frequency and multiplying it by a reference signal which is a signal having the same frequency as the detection target signal.
  • FIG. 1 is a graph illustrating a waveform showing a signal containing noise on the time axis
  • FIG. 2 is a graph showing a waveform showing a signal containing noise on the frequency axis.
  • white noise which is a noise of constant density, is superimposed on a sine wave of 1 kHz and 4 kHz over a wide band.
  • the detection of the fine signal detects a target signal such as detecting only a signal having a specific frequency, for example, a 1 kHz frequency, among signals having a waveform including white noise.
  • FIG 3 is a view for explaining an embodiment of detecting a fine signal using a conventional lock-in amplifier.
  • noise is included in a signal to be detected at a frequency f s over a wide frequency band.
  • the same frequency in the total signal i.e. in Figure 3 by multiplying a reference signal having a frequency of f s (b) a and the 2f s agreement frequency component, as shown in A direct current (DC) component that is a frequency component of the difference is obtained.
  • the magnitude of the DC component which is the frequency component of the difference is proportional to the amplitude of the signal to be detected.
  • a low pass filter is applied to the next obtained signal, only the frequency components of the difference are obtained because the sum frequency components are removed as shown in Fig. 3C.
  • the signal to be detected is converted into a low frequency as a direct current (DC) component having a magnitude proportional to its amplitude, and the noise passing through the low pass filter overlaps the direct current (DC) component and gradually changes.
  • the level of the detection target signal does not change and only the noise level is reduced, thereby effectively removing the noise generated from the outside of the detection apparatus, thereby detecting the fine signal.
  • SNR signal-to-noise ratio
  • DC direct current
  • the present invention has been made in an effort to provide a fine signal detection apparatus capable of improving detection sensitivity of a fine signal by using a signal having a high SNR when detecting a target signal of a desired frequency band from an input signal. .
  • the reference signal generating unit for generating and outputting a reference signal having the same frequency as the frequency of the detection signal included in the input signal;
  • a frequency mixer for generating a composite signal by multiplying the input signal by the reference signal;
  • a filtering unit configured to extract a signal corresponding to a second harmonic component of the frequency of the detection target signal from the synthesized signal;
  • a signal detector configured to detect the detection target signal from the signal output from the filtering unit.
  • noise that affects signal detection by selectively detecting a DC component or a harmonic component among components obtained by multiplying an input signal by a reference signal having a frequency equal to the frequency of the detection target signal Can be effectively suppressed to improve the detection sensitivity of the fine signal.
  • 1 and 2 are graphs showing a waveform showing a signal containing noise on the time axis and a waveform showing a signal containing noise on the frequency axis, respectively;
  • FIG. 3 is a view for explaining an embodiment of detecting a fine signal using a conventional lock-in amplifier
  • FIG. 4 is a view showing an example of a system to which a fine signal detection apparatus according to the present invention can be applied;
  • FIG. 5 is a view showing the configuration of a preferred embodiment of a fine signal detection apparatus according to the present invention.
  • FIG. 6 is a diagram illustrating an example in which a synthesized signal is generated by a frequency mixer
  • FIG. 8 is a graph showing an example of a synthesized signal used in the fine signal detection apparatus according to the present invention.
  • FIG. 10 is a view showing the configuration of a second preferred embodiment of a fine signal detection apparatus according to the present invention.
  • FIG. 11 is a diagram showing the configuration of the third preferred embodiment of the fine signal detection apparatus according to the present invention.
  • FIG. 4 is a diagram illustrating an example of a system to which a fine signal detection apparatus according to the present invention can be applied.
  • the reference signal generated and output by the oscillator is input to a laser diode driver to operate a laser diode (LD).
  • the optical signal output from the laser diode is input to a photodiode (PD) through a sensor, converted into an electrical signal, and then passed through a transimpedance amplifier (TIA) and a low-noise amplifier (LNA). It is input to the lock-in amplifier as described.
  • PD photodiode
  • TIA transimpedance amplifier
  • LNA low-noise amplifier
  • the lock-in amplifier detects a detection target signal by combining a reference signal output from the oscillator and an input signal input from a low noise amplifier.
  • the detected detection target signal is converted by the AD converter and input to the micro control unit which performs signal processing.
  • the fine signal detecting apparatus detects a detection target signal from an input signal by performing the same function as the lock-in amplifier in the system shown in FIG. 4.
  • FIG. 5 is a diagram showing the configuration of the first preferred embodiment of the apparatus for detecting fine signals according to the present invention.
  • the apparatus for detecting fine signals includes a reference signal generator 110, a frequency mixer 120, a filter 130, and a signal detector 140.
  • the reference signal generator 110 generates and outputs a reference signal having the same frequency as that of the detection target signal included in the input signal.
  • the reference signal generator 110 corresponds to the same component as an apparatus for generating a reference signal respectively input to the sensor and the lock-in amplifier in the system as shown in FIG. 4.
  • the signal may be used as the reference signal.
  • a reference signal having the same frequency as the detection target signal is used to extract the detection target signal.
  • the reference signal generator 110 is implemented as a voltage-controlled oscillator (VCO) to convert the reference signal. Can be generated. Also, other means such as a function generator other than the VCO may generate and output a reference signal having the same frequency as the signal to be detected.
  • VCO voltage-controlled oscillator
  • the frequency mixer 120 generates a composite signal by multiplying the input signal by the reference signal.
  • the input signal input to the frequency mixer 120 is the same as the signal output from the sensor and input to the lock-in amplifier in the system as shown in FIG. 4.
  • the detection target signal S 1 included in the input signal is a signal having a frequency of ⁇ .
  • the reference signal generator 110 generates a reference signal S 2 having the same frequency ⁇ as the detection target signal S 1
  • the frequency mixing unit 120 generates the detection signal S 1 and the reference signal ( Multiply S 2 ) to produce a composite signal.
  • the synthesized signal includes a direct current (DC) component, which is the frequency component of the difference, and a second harmonic component, which is the frequency component of the sum.
  • the frequency of the second harmonic component is 2 ⁇ , which is twice the frequency of the detection target signal S 1 .
  • the generation of the synthesized signal by the frequency mixer 120 is expressed as a formula below.
  • the detection target signal Acos ( ⁇ + ⁇ ) having an amplitude of A is included in the input signal
  • the synthesized signal is expressed as in Equation 1 below.
  • Equation 1 The right side of Equation 1 represents a synthesized signal, Is the direct current component, and Is the second harmonic component.
  • the detection target signal Acos ( ⁇ + ⁇ ) having an amplitude of A is included in the input signal
  • the reference signal -sin ( ⁇ ) having the same frequency is multiplied by the input signal and the synthesized signal is It is expressed as Equation 2.
  • the filtering unit 130 extracts a signal corresponding to the second harmonic component of the frequency of the detection target signal from the synthesized signal.
  • FIG. 7 is a graph showing the size of each frequency component included in a synthesized signal obtained by multiplying an input signal and a reference signal with noise.
  • the magnitudes of the direct current (DC) component and the second harmonic component of the detection target signal included in the synthesized signal are the same, which can be seen from Equations 1 and 2 above.
  • the amount of noise included in the synthesized signal varies with frequency, and generally increases with low frequency due to the influence of 1 / f noise.
  • the signal-to-noise ratio (SNR) of the direct current (DC) component is lower than that of the second harmonic component, and the detection sensitivity of the detection target signal is lowered.
  • the filtering unit 130 of the present invention improves the detection sensitivity of the fine signal by using a band pass filter corresponding to the frequency of the second harmonic component having a high SNR. That is, the signal of the second harmonic component of frequency 2 ⁇ is extracted from the two components of the synthesized signal shown in FIG.
  • the bandwidth of the filter is set differently according to the amount of noise included in the input signal, and preferably set to a bandwidth of 10 to 20 kHz based on the frequency of the second harmonic component.
  • the third harmonic component, the fourth harmonic component, and the like which are not the second harmonic component, may be extracted and used to detect the detection target signal, but these harmonic components have a low noise level, but the magnitude of the detection target signal may also be applied to the second harmonic component. Since it is relatively small, it is most preferable to extract the second harmonic component.
  • the signal detector 140 detects a detection target signal from the signal output from the filtering unit 130.
  • the detection target signal is detected from the signal of the second harmonic component whose SNR is higher than that of the direct current (DC) component, the sensitivity of signal detection is improved by attenuating the influence of 1 / f noise on the detection of the fine signal. You can.
  • the filtering unit 130 may apply a low pass filter and a band pass filter to the synthesized signal to extract signals corresponding to the direct current (DC) component and the second harmonic component, respectively.
  • DC direct current
  • the filtering unit 130 may apply a low pass filter and a band pass filter to the synthesized signal to extract signals corresponding to the direct current (DC) component and the second harmonic component, respectively.
  • it means to extract both the direct current (DC) component of frequency 0 and the signal of the second harmonic component of frequency 2 ⁇ from the synthesized signal shown in FIG.
  • the SNR at a frequency corresponding to a direct current (DC) component in a synthesized signal is generally low for a frequency corresponding to a second harmonic component due to the influence of 1 / f noise. It may appear.
  • the filtering unit 130 extracts a signal corresponding to a direct current (DC) component using a low pass filter to increase the detection sensitivity of the fine signal, and corresponds to a second harmonic component using a band pass filter. Extract the signal.
  • the bandwidth of the filter may be set under the same conditions as described above.
  • the signal detector 140 compares the SNRs of the two signals to obtain a signal having a relatively low noise level, that is, an SNR.
  • the detection target signal is detected from this high signal.
  • FIG. 8 is a graph showing an example of the synthesized signal used in the fine signal detection apparatus according to the present invention.
  • the reference signal having the same frequency as the specific detection target signal is mixed with the data of the semiconductor component.
  • DC direct current
  • FIG. 9 is a graph showing the magnitude of 1 / f noise detected according to the frequency.
  • the magnitude of 1 / f noise is larger in the low frequency band, and in particular, in the low frequency band, the magnitude of the 1 / f noise increases rapidly toward the DC component. Therefore, when the second harmonic component is extracted by the band pass filter and used to detect the detection target signal as in the present invention, the influence of the 1 / f noise can be suppressed and the sensitivity of the signal detection can be improved.
  • the magnitude of the noise according to the frequency is shown in Fig. 9, when the frequency of the second harmonic component is located in a low frequency band of 10 MHz or less, the bandwidth of the band pass filter is a low frequency band in which the magnitude of the noise increases rapidly. It is preferable not to include it.
  • FIG. 10 is a diagram showing the configuration of the second preferred embodiment of the apparatus for detecting fine signals according to the present invention.
  • the reference signal generator 110 of the apparatus for detecting a fine signal is implemented as a phase locked loop (PLL) to generate a reference signal having the same phase as a signal to be detected.
  • PLL phase locked loop
  • the phase of the detection target signal and the reference signal coincide with each other in order to keep the frequency of the reference signal constant at all times while accurately extracting a signal of a DC component and a second harmonic component from the synthesized signal.
  • the reference signal generator 110 includes a voltage controlled oscillator 112, a mixer 114, and an integrator 116.
  • the reference signal generator 110 generates and outputs a reference signal having the same frequency as the detection target signal included in the input signal, and adjusts the frequency of the reference signal by a control voltage received from the outside.
  • the mixer 114 generates a sub-synthesized signal by multiplying the reference signal output from the voltage-controlled oscillator 112 and the input signal, and the integrator 116 receives the sub-synthesized signal to control the voltage-controlled oscillator 112. Output voltage.
  • the control voltage is output based on the phase difference between the reference signal and the input signal, so that the phase of the input signal and the reference signal output from the voltage controlled oscillator 112 are the same.
  • FIG. 11 is a diagram showing the configuration of the third preferred embodiment of the fine signal detection apparatus according to the present invention.
  • the reference signal generator 110 generates and outputs a first reference signal having the same frequency as the detection target signal and a second reference signal having the same frequency as the first reference signal and having a phase difference of 90 °. .
  • the phase difference between the first reference signal and the second reference signal can be set by a phase shifter.
  • the frequency mixer 120 is composed of two mixers each receiving a first reference signal and a second reference signal, each mixer having a first synthesized signal and a second reference signal multiplied by a first reference signal and an input signal. A second synthesized signal multiplied by the input signal is generated.
  • the filtering unit 130 also includes two band pass filters to extract a signal corresponding to the second harmonic component from the first synthesized signal and the second synthesized signal, respectively.
  • the filtering unit 130 may be composed of two low pass filters to extract signals corresponding to direct current (DC) components from the first synthesized signal and the second synthesized signal, respectively.
  • the signal detector 140 receives two second harmonic components or two DC components.
  • the signal detector 140 creates a graph in which the horizontal axis is the sin axis and the vertical axis is the cos axis based on the magnitudes of the two signal components. Since the phase difference between the first reference signal and the second reference signal is 90 °, a linear graph showing the magnitude of each component can be obtained using sin and cos as the coordinate axes, and the magnitude and phase of the signal to be detected can be calculated from the graph. have.

Abstract

Disclosed is a fine signal detector. A reference signal generation unit generates and outputs a reference signal that has the same frequency as a signal to be detected which is included in an input signal. A frequency mixing unit multiplies the input signal by the reference signal and generates a synthesis signal. A filtering part extracts from the synthesis signal a signal corresponding to a second harmonic component with respect to the frequency of the signal to be detected. A signal detection unit detects a signal to be detected from the signal that is output by the filtering unit. By selectively detecting either a direct current component or a harmonic component among the components that are obtained by multiplying the input signal by the reference signal having the same frequency as the signal to be detected, the present invention enables effective suppression of noise that impacts signal detection, thereby enhancing the detection sensibility of fine signals.

Description

미세 신호 검출장치Fine signal detector
본 발명은 미세 신호 검출장치에 관한 것으로, 보다 상세하게는 상대적으로 큰 레벨의 노이즈가 포함된 신호로부터 원하는 신호를 검출하기 위한 장치에 관한 것이다.The present invention relates to an apparatus for detecting a fine signal, and more particularly, to an apparatus for detecting a desired signal from a signal containing a relatively large level of noise.
미세 신호를 검출할 때 신호에 비해 상대적으로 큰 레벨로 포함되어 있는 노이즈의 영향으로 필요한 정밀도를 얻을 수 없는 경우가 많다. 미세 신호 검출에 영향을 미치는 노이즈는 유도 결합이나 용량 결합에 의해 신호선에 발생하는 노이즈, 전원에 혼입되어 있는 노이즈, 그라운드 전위의 차이나 그라운드를 흐르는 전류에 의한 노이즈, 증폭기 내부에서 발생하는 노이즈, 신호에 원래 포함되어 있는 노이즈나 센서 자체가 발생하는 노이즈 등이 있다.When detecting a fine signal, it is often impossible to obtain the required precision due to the influence of noise contained at a relatively higher level than the signal. Noise affecting the detection of fine signals is noise generated on the signal line by inductive coupling or capacitive coupling, noise mixed into the power supply, noise caused by a difference in ground potential or current flowing through the ground, noise generated inside the amplifier, and a signal. Originally included noise or noise generated by the sensor itself.
이러한 노이즈의 영향을 받지 않고 미세 신호를 검출하기 위해 사용되는 것이 락인 앰프(Lock-in amplifier)이다. 락인 앰프는 검출기의 형태로서, 부분적 또는 완전하게 노이즈에 묻혀있는 신호를 복원하는 앰프이다. 실제로 검출하려는 신호보다 훨씬 더 큰 노이즈가 있을 때 많이 사용된다. 락인 앰프는 광대역 검출 대상 신호를 특정 주파수를 이용하며, 여기에 검출 대상 신호와 동일한 주파수를 가지는 신호인 기준 신호(reference signal)를 곱하여 검출 대상 신호의 크기 성분을 추출할 수 있다. A lock-in amplifier is used to detect a fine signal without being affected by such noise. A lock-in amplifier is a detector that recovers a signal that is partially or completely buried in noise. It is often used when there is much louder noise than the signal to actually detect. The lock-in amplifier may extract a magnitude component of the detection target signal by multiplying the wideband detection target signal by using a specific frequency and multiplying it by a reference signal which is a signal having the same frequency as the detection target signal.
도 1은 노이즈가 포함된 신호를 시간축에서 나타낸 파형, 도 2는 노이즈가 포함된 신호를 주파수축에서 나타낸 파형을 도시한 그래프이다. 도 1 및 도 2를 참조하면, 1kHz와 4kHz의 정현파에 넓은 대역에 걸쳐 일정한 밀도의 노이즈인 화이트 노이즈(white noise)가 중첩되어 있다. 미세 신호의 검출은 이와 같이 화이트 노이즈가 포함된 파형을 가지는 신호 중에서 특정한 주파수, 예를 들면 1kHz 주파수의 신호만 검출하는 등 목적하는 신호를 검출하는 것이다.1 is a graph illustrating a waveform showing a signal containing noise on the time axis, and FIG. 2 is a graph showing a waveform showing a signal containing noise on the frequency axis. 1 and 2, white noise, which is a noise of constant density, is superimposed on a sine wave of 1 kHz and 4 kHz over a wide band. The detection of the fine signal detects a target signal such as detecting only a signal having a specific frequency, for example, a 1 kHz frequency, among signals having a waveform including white noise.
도 3은 기존의 락인 앰프를 이용하여 미세 신호를 검출하는 일 실시예를 설명하기 위한 도면이다.3 is a view for explaining an embodiment of detecting a fine signal using a conventional lock-in amplifier.
도 3의 (a)를 참조하면, fs 주파수의 검출대상 신호에 넓은 주파수 대역에 걸쳐 노이즈가 포함되어 있다. 노이즈가 포함된 전체 신호 중에서 검출대상 신호만을 검출하기 위해 전체 신호에 동일한 주파수, 즉 fs의 주파수를 가진 기준 신호를 곱하면 도 3의 (b)에 도시된 바와 같이 합의 주파수 성분인 2fs와 차의 주파수 성분인 직류(DC) 성분이 얻어진다. 여기서, 차의 주파수 성분인 직류(DC) 성분의 크기는 검출대상 신호의 진폭에 비례한다. 다음으로 얻어진 신호에 저역 통과 필터(Low Pass Filter)를 적용하면, 도 3의 (c)에 도시된 바와 같이 합의 주파수 성분은 제거되기 때문에 차의 주파수 성분만이 얻어진다. 결과적으로 검출대상 신호는 그 진폭에 비례하는 크기를 가진 직류(DC)성분으로서 낮은 주파수로 변환되고, 저역 통과 필터를 통과한 노이즈는 그 직류(DC)성분에 중첩되어 서서히 변동하게 된다.Referring to FIG. 3A, noise is included in a signal to be detected at a frequency f s over a wide frequency band. Of the total signal comprising the noise to detect only the detected signal the same frequency in the total signal, i.e. in Figure 3 by multiplying a reference signal having a frequency of f s (b) a and the 2f s agreement frequency component, as shown in A direct current (DC) component that is a frequency component of the difference is obtained. Here, the magnitude of the DC component which is the frequency component of the difference is proportional to the amplitude of the signal to be detected. When a low pass filter is applied to the next obtained signal, only the frequency components of the difference are obtained because the sum frequency components are removed as shown in Fig. 3C. As a result, the signal to be detected is converted into a low frequency as a direct current (DC) component having a magnitude proportional to its amplitude, and the noise passing through the low pass filter overlaps the direct current (DC) component and gradually changes.
이와 같이 락인 앰프를 사용하여 낮은 주파수 대역의 신호만을 검출하게 되면 검출대상 신호의 레벨은 변하지 않고 노이즈의 크기만 감소하기 때문에 검출장치 외부에서 생성되는 노이즈를 효과적으로 제거하여 미세 신호를 검출할 수 있다. 하지만 검출 회로 내의 전자 부품들에 의한 1/f 노이즈에 의해 직류(DC)성분의 신호 대 잡음비(Signal to noise ratio:SNR)가 열화되어 검출대상 신호의 레벨보다 노이즈 레벨이 높게 유지되는 경우가 존재한다. 따라서, 1/f 노이즈의 영향을 피하고 검출 감도가 높은 미세 신호의 검출방법이 요구된다.When only a signal of a low frequency band is detected using the lock-in amplifier as described above, the level of the detection target signal does not change and only the noise level is reduced, thereby effectively removing the noise generated from the outside of the detection apparatus, thereby detecting the fine signal. However, there are cases where the signal-to-noise ratio (SNR) of the direct current (DC) component is degraded by 1 / f noise caused by electronic components in the detection circuit, so that the noise level is maintained higher than the level of the signal to be detected. do. Therefore, there is a need for a method for detecting a fine signal having high detection sensitivity while avoiding the influence of 1 / f noise.
본 발명이 이루고자 하는 기술적 과제는, 입력 신호로부터 목적하는 주파수 대역의 검출대상 신호를 검출할 때 SNR이 높은 신호를 이용함으로써 미세 신호의 검출감도를 향상시킬 수 있는 미세 신호 검출장치를 제공하는 데 있다.SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a fine signal detection apparatus capable of improving detection sensitivity of a fine signal by using a signal having a high SNR when detecting a target signal of a desired frequency band from an input signal. .
상기의 기술적 과제를 달성하기 위한, 본 발명에 따른 미세 신호 검출장치는, 입력 신호에 포함된 검출대상 신호의 주파수와 동일한 주파수를 가지는 기준 신호를 생성하여 출력하는 기준 신호 생성부; 상기 입력 신호와 상기 기준 신호를 곱하여 합성 신호를 생성하는 주파수 혼합부; 상기 합성 신호로부터 상기 검출대상 신호의 주파수에 대한 제2고조파 성분에 해당하는 신호를 추출하는 필터링부; 및 상기 필터링부에서 출력된 신호로부터 상기 검출대상 신호를 검출하는 신호 검출부;를 구비한다.In order to achieve the above technical problem, the micro-signal detecting apparatus according to the present invention, the reference signal generating unit for generating and outputting a reference signal having the same frequency as the frequency of the detection signal included in the input signal; A frequency mixer for generating a composite signal by multiplying the input signal by the reference signal; A filtering unit configured to extract a signal corresponding to a second harmonic component of the frequency of the detection target signal from the synthesized signal; And a signal detector configured to detect the detection target signal from the signal output from the filtering unit.
본 발명에 따른 미세 신호 검출장치에 의하면, 검출대상 신호의 주파수와 동일한 주파수를 가지는 기준 신호를 입력 신호에 곱하여 얻어진 성분들 중에서 직류 성분 또는 고조파 성분을 선택적으로 검출함으로써, 신호 검출에 영향을 미치는 노이즈를 효과적으로 억제하여 미세 신호의 검출감도를 향상시킬 수 있다.According to the microsignal detecting apparatus according to the present invention, noise that affects signal detection by selectively detecting a DC component or a harmonic component among components obtained by multiplying an input signal by a reference signal having a frequency equal to the frequency of the detection target signal Can be effectively suppressed to improve the detection sensitivity of the fine signal.
도 1 및 도 2는 각각 노이즈가 포함된 신호를 시간축에서 나타낸 파형 및 노이즈가 포함된 신호를 주파수축에서 나타낸 파형을 도시한 그래프,1 and 2 are graphs showing a waveform showing a signal containing noise on the time axis and a waveform showing a signal containing noise on the frequency axis, respectively;
도 3은 기존의 락인 앰프를 이용하여 미세 신호를 검출하는 일 실시예를 설명하기 위한 도면,3 is a view for explaining an embodiment of detecting a fine signal using a conventional lock-in amplifier,
도 4는 본 발명에 따른 미세 신호 검출장치가 적용될 수 있는 시스템의 일 예를 도시한 도면,4 is a view showing an example of a system to which a fine signal detection apparatus according to the present invention can be applied;
도 5는 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 일 실시예의 구성을 도시한 도면,5 is a view showing the configuration of a preferred embodiment of a fine signal detection apparatus according to the present invention,
도 6은 주파수 혼합부에 의해 합성 신호가 생성되는 일 예를 도시한 도면,6 is a diagram illustrating an example in which a synthesized signal is generated by a frequency mixer;
도 7은 입력 신호와 기준 신호를 곱하여 얻어진 합성 신호에 포함된 각 주파수 성분의 크기를 노이즈와 함께 도시한 그래프,7 is a graph showing the size of each frequency component included in a synthesized signal obtained by multiplying an input signal and a reference signal with noise;
도 8은 본 발명에 따른 미세 신호 검출장치에서 사용된 합성 신호의 일 예를 도시한 그래프,8 is a graph showing an example of a synthesized signal used in the fine signal detection apparatus according to the present invention;
도 9는 주파수에 따라 검출된 1/f 노이즈의 크기를 도시한 그래프,9 is a graph showing the magnitude of 1 / f noise detected according to a frequency;
도 10은 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 제2실시예의 구성을 도시한 도면, 그리고,10 is a view showing the configuration of a second preferred embodiment of a fine signal detection apparatus according to the present invention; and
도 11은 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 제3실시예의 구성을 도시한 도면이다.11 is a diagram showing the configuration of the third preferred embodiment of the fine signal detection apparatus according to the present invention.
이하에서 첨부된 도면들을 참조하여 본 발명에 따른 미세 신호 검출장치의 바람직한 실시예에 대해 상세하게 설명한다.Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the fine signal detection apparatus according to the present invention.
도 4는 본 발명에 따른 미세 신호 검출장치가 적용될 수 있는 시스템의 일 예를 도시한 도면이다.4 is a diagram illustrating an example of a system to which a fine signal detection apparatus according to the present invention can be applied.
도 4를 참조하면, 발진기에 의해 생성되어 출력된 기준 신호는 레이저 다이오드 드라이버(Laser Diode Driver)로 입력되어 레이저 다이오드(Laser Diode : LD)를 동작시킨다. 레이저 다이오드로부터 출력된 광신호는 센서를 거쳐 포토다이오드(PhotoDiode : PD)에 입력되어 전기 신호로 변환된 후, 전치 증폭기(TransImpedance Amplifier : TIA) 및 저잡음 증폭기(Low-Noise Amplifier : LNA)를 거쳐 앞에서 설명한 것과 같은 락인앰프로 입력된다.Referring to FIG. 4, the reference signal generated and output by the oscillator is input to a laser diode driver to operate a laser diode (LD). The optical signal output from the laser diode is input to a photodiode (PD) through a sensor, converted into an electrical signal, and then passed through a transimpedance amplifier (TIA) and a low-noise amplifier (LNA). It is input to the lock-in amplifier as described.
락인앰프에서는 발진기로부터 출력된 기준 신호와 저잡음 증폭기로부터 입력받은 입력 신호를 합성하여 검출대상 신호를 검출한다. 검출된 검출대상 신호는 AD 컨버터에 의해 변환된 후 신호 처리를 수행하는 마이크로 컨트롤 유닛으로 입력된다. 본 발명에 따른 미세 신호 검출장치는 도 4에 도시된 시스템 중에서 락인앰프와 동일한 기능을 수행하여 입력 신호로부터 검출대상 신호를 검출하는 것이다.The lock-in amplifier detects a detection target signal by combining a reference signal output from the oscillator and an input signal input from a low noise amplifier. The detected detection target signal is converted by the AD converter and input to the micro control unit which performs signal processing. The fine signal detecting apparatus according to the present invention detects a detection target signal from an input signal by performing the same function as the lock-in amplifier in the system shown in FIG. 4.
도 5는 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 제1실시예의 구성을 도시한 도면이다.5 is a diagram showing the configuration of the first preferred embodiment of the apparatus for detecting fine signals according to the present invention.
도 5를 참조하면, 본 발명에 따른 미세 신호 검출장치는 기준 신호 생성부(110), 주파수 혼합부(120), 필터링부(130) 및 신호 검출부(140)를 구비한다.Referring to FIG. 5, the apparatus for detecting fine signals according to the present invention includes a reference signal generator 110, a frequency mixer 120, a filter 130, and a signal detector 140.
기준 신호 생성부(110)는 입력 신호에 포함된 검출대상 신호의 주파수와 동일한 주파수를 가지는 기준 신호를 생성하여 출력한다. 이때 기준 신호 생성부(110)는 도 4에 도시된 것과 같은 시스템에서 센서 및 락인앰프로 각각 입력되는 기준 신호를 생성하는 장치와 동일한 구성요소에 해당한다. 또는 인위적으로 기준 신호를 생성하지 않고 센서로 입력되는 다른 신호가 있는 경우에 해당 신호를 기준 신호로서 사용할 수도 있다.The reference signal generator 110 generates and outputs a reference signal having the same frequency as that of the detection target signal included in the input signal. In this case, the reference signal generator 110 corresponds to the same component as an apparatus for generating a reference signal respectively input to the sensor and the lock-in amplifier in the system as shown in FIG. 4. Alternatively, when there is another signal input to the sensor without artificially generating a reference signal, the signal may be used as the reference signal.
앞에서 설명한 바와 같이 검출대상 신호를 추출하기 위해 검출대상 신호와 동일한 주파수를 가지는 기준 신호가 사용되는데, 기준 신호 생성부(110)는 전압 제어 발진기(Voltage-Controlled Oscillator : VCO)로 구현되어 기준 신호를 발생시킬 수 있다. 또한 VCO가 아닌 함수 발생기 등의 다른 수단에 의해 검출대상 신호와 동일한 주파수를 가지는 기준 신호를 생성하여 출력할 수도 있다.As described above, a reference signal having the same frequency as the detection target signal is used to extract the detection target signal. The reference signal generator 110 is implemented as a voltage-controlled oscillator (VCO) to convert the reference signal. Can be generated. Also, other means such as a function generator other than the VCO may generate and output a reference signal having the same frequency as the signal to be detected.
주파수 혼합부(120)는 입력 신호와 기준 신호를 곱하여 합성 신호를 생성한다. 주파수 혼합부(120)로 입력되는 입력 신호는 도 4에 도시된 것과 같은 시스템에서 센서로부터 출력되어 락인 앰프로 입력되는 신호와 동일하다.The frequency mixer 120 generates a composite signal by multiplying the input signal by the reference signal. The input signal input to the frequency mixer 120 is the same as the signal output from the sensor and input to the lock-in amplifier in the system as shown in FIG. 4.
도 6은 주파수 혼합부(120)에 의해 합성 신호가 생성되는 일 예를 도시한 도면이다. 도 6을 참조하면, 입력 신호에 포함된 검출대상 신호(S1)는 ω의 주파수를 가지는 신호이다. 설명의 편의를 위해 입력 신호에 포함된 노이즈는 도시하지 않았다. 따라서 기준 신호 생성부(110)는 검출대상 신호(S1)와 동일한 주파수 ω를 가지는 기준 신호(S2)를 생성하고, 주파수 혼합부(120)는 검출대상 신호(S1)와 기준 신호(S2)를 곱하여 합성 신호를 생성한다. 합성 신호에는 차의 주파수 성분인 직류(DC) 성분과 합의 주파수 성분인 제2고조파 성분이 포함되어 있다. 제2고조파 성분의 주파수는 검출대상 신호(S1)의 주파수의 두 배인 2ω이다.6 is a diagram illustrating an example in which a synthesized signal is generated by the frequency mixer 120. Referring to FIG. 6, the detection target signal S 1 included in the input signal is a signal having a frequency of ω. For convenience of description, noise included in the input signal is not shown. Therefore, the reference signal generator 110 generates a reference signal S 2 having the same frequency ω as the detection target signal S 1 , and the frequency mixing unit 120 generates the detection signal S 1 and the reference signal ( Multiply S 2 ) to produce a composite signal. The synthesized signal includes a direct current (DC) component, which is the frequency component of the difference, and a second harmonic component, which is the frequency component of the sum. The frequency of the second harmonic component is 2 ω, which is twice the frequency of the detection target signal S 1 .
주파수 혼합부(120)에 의한 합성 신호의 생성을 수식으로 표현하면 다음과 같다. 진폭이 A인 검출대상 신호 Acos(ω+θ)가 입력 신호에 포함되어 있는 경우, 동일한 주파수를 가지는 기준 신호 cos(ω)를 입력 신호에 곱하면 합성 신호는 다음의 수학식 1과 같이 표현된다.The generation of the synthesized signal by the frequency mixer 120 is expressed as a formula below. In the case where the detection target signal Acos (ω + θ) having an amplitude of A is included in the input signal, when the reference signal cos (ω) having the same frequency is multiplied by the input signal, the synthesized signal is expressed as in Equation 1 below. .
수학식 1
Figure PCTKR2009005944-appb-M000001
 Equation 1
Figure PCTKR2009005944-appb-M000001
수학식 1의 우변은 합성 신호를 나타내며,
Figure PCTKR2009005944-appb-I000001
는 직류 성분, 그리고
Figure PCTKR2009005944-appb-I000002
는 제2고조파 성분이다.The right side of Equation 1 represents a synthesized signal,
Figure PCTKR2009005944-appb-I000001
Is the direct current component, and
Figure PCTKR2009005944-appb-I000002
Is the second harmonic component.
또 다른 예로서, 진폭이 A인 검출대상 신호 Acos(ω+θ)가 입력 신호에 포함되어 있는 경우, 동일한 주파수를 가지는 기준 신호 -sin(ω)를 입력 신호에 곱하면 합성 신호는 다음의 수학식 2와 같이 표현된다.As another example, when the detection target signal Acos (ω + θ) having an amplitude of A is included in the input signal, the reference signal -sin (ω) having the same frequency is multiplied by the input signal and the synthesized signal is It is expressed as Equation 2.
수학식 2
Figure PCTKR2009005944-appb-M000002
 Equation 2
Figure PCTKR2009005944-appb-M000002
여기서, 우변은 합성 신호를 나타내며,
Figure PCTKR2009005944-appb-I000003
는 직류 성분, 그리고
Figure PCTKR2009005944-appb-I000004
는 제2고조파 성분이다.Where the right side represents the composite signal,
Figure PCTKR2009005944-appb-I000003
Is the direct current component, and
Figure PCTKR2009005944-appb-I000004
Is the second harmonic component.
필터링부(130)는 합성 신호로부터 검출대상 신호의 주파수에 대한 제2고조파 성분에 해당하는 신호를 추출한다.The filtering unit 130 extracts a signal corresponding to the second harmonic component of the frequency of the detection target signal from the synthesized signal.
앞에서 설명한 바와 같이 기존의 미세 신호 검출장치에서는 합성 신호에 저역 통과 필터를 적용하여 직류(DC) 성분을 추출함으로써 미세 신호를 검출하는 방법을 사용하였다. 그러나 1/f 노이즈의 영향으로 미세 신호의 검출 감도가 저하된다는 문제를 가지고 있었다.As described above, in the conventional fine signal detection apparatus, a method of detecting a fine signal by extracting a direct current (DC) component by applying a low pass filter to the synthesized signal is used. However, there is a problem that the detection sensitivity of the fine signal is lowered under the influence of 1 / f noise.
도 7은 입력 신호와 기준 신호를 곱하여 얻어진 합성 신호에 포함된 각 주파수 성분의 크기를 노이즈와 함께 도시한 그래프이다.FIG. 7 is a graph showing the size of each frequency component included in a synthesized signal obtained by multiplying an input signal and a reference signal with noise.
도 7을 참조하면, 합성 신호에 포함된 검출대상 신호의 직류(DC) 성분과 제2고조파 성분의 크기는 동일하며, 이는 앞의 수학식 1 및 수학식 2로부터도 알 수 있다. 그러나 합성 신호에 포함된 노이즈의 크기는 주파수에 따라 달라지는데, 보통 1/f 노이즈의 영향으로 낮은 주파수로 갈수록 증가하는 경향을 보인다. 그 결과 직류(DC) 성분의 신호 대 잡음비(Signal to Noise Ratio : SNR)가 제2고조파 성분의 SNR에 비해 낮아지며, 검출대상 신호의 검출 감도가 저하되는 것이다.Referring to FIG. 7, the magnitudes of the direct current (DC) component and the second harmonic component of the detection target signal included in the synthesized signal are the same, which can be seen from Equations 1 and 2 above. However, the amount of noise included in the synthesized signal varies with frequency, and generally increases with low frequency due to the influence of 1 / f noise. As a result, the signal-to-noise ratio (SNR) of the direct current (DC) component is lower than that of the second harmonic component, and the detection sensitivity of the detection target signal is lowered.
이와 같은 문제를 해결하기 위해 본 발명의 필터링부(130)는 SNR이 높은 제2고조파 성분의 주파수에 해당하는 대역 통과 필터를 사용하여 미세 신호의 검출 감도를 향상시킨다. 즉, 도 6에 도시된 합성 신호의 두 가지 성분 중에서 주파수 2ω의 제2고조파 성분의 신호를 추출한다. 이때 필터의 대역폭은 입력 신호에 포함된 노이즈의 크기에 따라 다르게 설정되며, 제2고조파 성분의 주파수를 중심으로 10 내지 20kHz의 대역폭으로 설정하는 것이 바람직하다. 또한 제2고조파 성분이 아닌 제3고조파 성분, 제4고조파 성분 등을 추출하여 검출대상 신호의 검출에 사용할 수도 있지만, 이러한 고조파 성분들은 노이즈 레벨이 낮은 대신 검출대상 신호의 크기도 제2고조파 성분에 비해 작기 때문에 제2고조파 성분을 추출하는 것이 가장 바람직하다.In order to solve this problem, the filtering unit 130 of the present invention improves the detection sensitivity of the fine signal by using a band pass filter corresponding to the frequency of the second harmonic component having a high SNR. That is, the signal of the second harmonic component of frequency 2ω is extracted from the two components of the synthesized signal shown in FIG. In this case, the bandwidth of the filter is set differently according to the amount of noise included in the input signal, and preferably set to a bandwidth of 10 to 20 kHz based on the frequency of the second harmonic component. In addition, the third harmonic component, the fourth harmonic component, and the like, which are not the second harmonic component, may be extracted and used to detect the detection target signal, but these harmonic components have a low noise level, but the magnitude of the detection target signal may also be applied to the second harmonic component. Since it is relatively small, it is most preferable to extract the second harmonic component.
마지막으로, 신호 검출부(140)는 필터링부(130)에서 출력된 신호로부터 검출대상 신호를 검출한다. 이상에서 설명한 바와 같이 직류(DC) 성분에 비해 SNR이 높은 제2고조파 성분의 신호로부터 검출대상 신호를 검출하기 때문에 미세 신호의 검출에 미치는 1/f 노이즈의 영향을 감쇠시켜 신호 검출의 감도를 향상시킬 수 있다.Finally, the signal detector 140 detects a detection target signal from the signal output from the filtering unit 130. As described above, since the detection target signal is detected from the signal of the second harmonic component whose SNR is higher than that of the direct current (DC) component, the sensitivity of signal detection is improved by attenuating the influence of 1 / f noise on the detection of the fine signal. You can.
한편, 필터링부(130)는 합성 신호에 대해 저역 통과 필터 및 대역 통과 필터를 적용하여 직류(DC) 성분 및 제2고조파 성분에 해당하는 신호를 각각 추출할 수도 있다. 이 경우는 도 6에 도시된 합성 신호로부터 주파수 0의 직류(DC) 성분과 주파수 2ω의 제2고조파 성분의 신호를 모두 추출하는 것을 말한다.Meanwhile, the filtering unit 130 may apply a low pass filter and a band pass filter to the synthesized signal to extract signals corresponding to the direct current (DC) component and the second harmonic component, respectively. In this case, it means to extract both the direct current (DC) component of frequency 0 and the signal of the second harmonic component of frequency 2ω from the synthesized signal shown in FIG.
도 7에 도시된 바와 같이 1/f 노이즈의 영향으로 합성 신호에서 직류(DC) 성분에 해당하는 주파수에서의 SNR이 제2고조파 성분에 해당하는 주파수에 대해 낮게 나타나는 것이 보통이지만, 반대의 형태로 나타나는 경우도 있다. 필터링부(130)는 이러한 경우에도 미세 신호의 검출 감도를 높게 하기 위해 저역 통과 필터를 사용하여 직류(DC) 성분에 해당하는 신호를 추출하고, 대역 통과 필터를 사용하여 제2고조파 성분에 해당하는 신호를 추출한다. 이때 필터의 대역폭은 앞에서 설명한 것과 동일한 조건으로 설정될 수 있다.As shown in FIG. 7, the SNR at a frequency corresponding to a direct current (DC) component in a synthesized signal is generally low for a frequency corresponding to a second harmonic component due to the influence of 1 / f noise. It may appear. Even in such a case, the filtering unit 130 extracts a signal corresponding to a direct current (DC) component using a low pass filter to increase the detection sensitivity of the fine signal, and corresponds to a second harmonic component using a band pass filter. Extract the signal. In this case, the bandwidth of the filter may be set under the same conditions as described above.
필터링부(130)에 의해 직류(DC) 성분과 제2고조파 성분의 신호가 모두 합성 신호로부터 추출되면, 신호 검출부(140)는 두 신호의 SNR을 비교하여 노이즈 레벨이 상대적으로 낮은 신호, 즉 SNR이 높은 신호로부터 검출대상 신호를 검출한다. 이와 같이 미세 신호의 검출 감도가 더 높은 성분을 선택적으로 검출대상 신호의 검출에 이용함으로써 1/f 노이즈의 영향을 최소화할 수 있다.When both the direct current (DC) component and the second harmonic component signal is extracted from the synthesized signal by the filtering unit 130, the signal detector 140 compares the SNRs of the two signals to obtain a signal having a relatively low noise level, that is, an SNR. The detection target signal is detected from this high signal. Thus, by selectively using a component having a higher detection sensitivity of the fine signal for detecting the detection target signal, the influence of 1 / f noise can be minimized.
도 8은 본 발명에 따른 미세 신호 검출장치에서 사용된 합성 신호의 일 예를 도시한 그래프이다. 반도체 부품의 데이터를 가지고 특정 검출대상 신호와 동일한 주파수를 가지는 기준 신호가 혼합되었으며, 도 8을 참조하면 검출대상 신호에 대해 주파수가 0인 직류(DC) 성분과 주파수가 약 200kHz인 제2고조파 성분이 노이즈와 함께 합성 신호에 포함된 것을 확인할 수 있다. 두 성분의 SNR을 비교하면, 직류(DC) 성분에 대하여는 SNR이 -35dB이며, 제2고조파 성분에 대하여는 SNR이 -65dB로 나타난다. 따라서 검출대상 신호를 검출할 때 제2고조파 성분을 사용하는 것이 더 바람직함을 확인할 수 있다.8 is a graph showing an example of the synthesized signal used in the fine signal detection apparatus according to the present invention. The reference signal having the same frequency as the specific detection target signal is mixed with the data of the semiconductor component. Referring to FIG. 8, a DC component having a frequency of 0 and a second harmonic component having a frequency of about 200 kHz for the detection target signal. It can be seen that the noise is included in the synthesized signal. Comparing the SNRs of the two components, the SNR is -35 dB for the direct current (DC) component and the SNR is -65 dB for the second harmonic component. Therefore, it can be seen that it is more preferable to use the second harmonic component when detecting the detection target signal.
또한 도 9는 주파수에 따라 검출된 1/f 노이즈의 크기를 도시한 그래프이다. 도 9를 참조하면, 1/f 노이즈의 크기는 저주파 대역에서 더 크게 나타나며, 특히 저주파 대역에서는 직류 성분으로 갈수록 급격하게 증가하는 것을 확인할 수 있다. 따라서 본 발명에서와 같이 대역 통과 필터에 의해 제2고조파 성분을 추출하여 검출대상 신호를 검출하는 데 사용하면 이러한 1/f 노이즈의 영향을 억제하고, 신호 검출의 감도를 향상시킬 수 있다. 한편, 주파수에 따른 노이즈의 크기가 도 9와 같이 나타날 때, 제2고조파 성분의 주파수가 10MHz 이하의 낮은 주파수 대역에 위치하는 경우에는 대역 통과 필터의 대역폭이 노이즈의 크기가 급격히 커지는 낮은 주파수 대역을 포함하지 않도록 하는 것이 바람직하다.9 is a graph showing the magnitude of 1 / f noise detected according to the frequency. Referring to FIG. 9, it can be seen that the magnitude of 1 / f noise is larger in the low frequency band, and in particular, in the low frequency band, the magnitude of the 1 / f noise increases rapidly toward the DC component. Therefore, when the second harmonic component is extracted by the band pass filter and used to detect the detection target signal as in the present invention, the influence of the 1 / f noise can be suppressed and the sensitivity of the signal detection can be improved. On the other hand, when the magnitude of the noise according to the frequency is shown in Fig. 9, when the frequency of the second harmonic component is located in a low frequency band of 10 MHz or less, the bandwidth of the band pass filter is a low frequency band in which the magnitude of the noise increases rapidly. It is preferable not to include it.
도 10은 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 제2실시예의 구성을 도시한 도면이다.10 is a diagram showing the configuration of the second preferred embodiment of the apparatus for detecting fine signals according to the present invention.
도 10을 참조하면, 본 발명에 따른 미세 신호 검출장치의 기준 신호 생성부(110)는 검출대상 신호와 동일한 위상을 가지는 기준 신호를 생성하기 위해 위상 고정 루프(Phase Locked Loop : PLL)로 구현된다. 검출대상 신호와 기준 신호의 위상을 일치시키는 것은 기준 신호의 주파수가 항상 일정하게 유지되도록 하는 한편 합성 신호에서 직류(DC) 성분과 제2고조파 성분의 신호를 정확하게 추출할 수 있도록 하기 위함이다.Referring to FIG. 10, the reference signal generator 110 of the apparatus for detecting a fine signal according to the present invention is implemented as a phase locked loop (PLL) to generate a reference signal having the same phase as a signal to be detected. . The phase of the detection target signal and the reference signal coincide with each other in order to keep the frequency of the reference signal constant at all times while accurately extracting a signal of a DC component and a second harmonic component from the synthesized signal.
도 10에 도시된 미세 신호 검출장치의 제2실시예에서 기준 신호 생성부(110)는 전압 제어 발진기(112), 혼합기(114) 및 적분기(116)로 구성된다. 기준 신호 생성부(110)는 입력 신호에 포함된 검출대상 신호와 동일한 주파수의 기준 신호를 생성하여 출력하되, 외부로부터 입력받은 제어 전압에 의해 기준 신호의 주파수를 조절한다. 혼합기(114)는 전압 제어 발진기(112)로부터 출력된 기준 신호와 입력 신호를 곱하여 서브 합성 신호를 생성하고, 적분기(116)는 서브 합성 신호를 입력받아 전압 제어 발진기(112)를 제어하기 위한 제어 전압을 출력한다. 제어 전압은 기준 신호와 입력 신호의 위상차를 기초로 하여 출력되며, 전압 제어 발진기(112)가 출력하는 기준 신호와 입력 신호의 위상이 동일하게 되도록 한다.In the second embodiment of the microsignal detecting apparatus shown in FIG. 10, the reference signal generator 110 includes a voltage controlled oscillator 112, a mixer 114, and an integrator 116. The reference signal generator 110 generates and outputs a reference signal having the same frequency as the detection target signal included in the input signal, and adjusts the frequency of the reference signal by a control voltage received from the outside. The mixer 114 generates a sub-synthesized signal by multiplying the reference signal output from the voltage-controlled oscillator 112 and the input signal, and the integrator 116 receives the sub-synthesized signal to control the voltage-controlled oscillator 112. Output voltage. The control voltage is output based on the phase difference between the reference signal and the input signal, so that the phase of the input signal and the reference signal output from the voltage controlled oscillator 112 are the same.
도 11은 본 발명에 따른 미세 신호 검출장치에 대한 바람직한 제3실시예의 구성을 도시한 도면이다.11 is a diagram showing the configuration of the third preferred embodiment of the fine signal detection apparatus according to the present invention.
도 11을 참조하면, 기준 신호 발생부(110)는 검출대상 신호와 동일한 주파수를 가지는 제1기준신호 및 제1기준신호와 주파수가 동일하고 위상차가 90°인 제2기준신호를 생성하여 출력한다. 제1기준신호와 제2기준신호의 위상차는 위상 천이기에 의해 설정할 수 있다.Referring to FIG. 11, the reference signal generator 110 generates and outputs a first reference signal having the same frequency as the detection target signal and a second reference signal having the same frequency as the first reference signal and having a phase difference of 90 °. . The phase difference between the first reference signal and the second reference signal can be set by a phase shifter.
주파수 혼합부(120)는 제1기준신호와 제2기준신호를 각각 입력받는 두 개의 혼합기로 구성되며, 각각의 혼합기는 제1기준신호와 입력신호를 곱한 제1합성신호 및 제2기준신호와 입력신호를 곱한 제2합성신호를 생성한다. 다음으로 필터링부(130) 역시 두 개의 대역 통과 필터로 구성되어 제1합성신호 및 제2합성신호로부터 각각 제2고조파 성분에 해당하는 신호를 추출한다. 한편, 필터링부(130)는 두 개의 저역 통과 필터로 구성되어 제1합성신호 및 제2합성신호로부터 각각 직류(DC) 성분에 해당하는 신호를 추출할 수도 있다.The frequency mixer 120 is composed of two mixers each receiving a first reference signal and a second reference signal, each mixer having a first synthesized signal and a second reference signal multiplied by a first reference signal and an input signal. A second synthesized signal multiplied by the input signal is generated. Next, the filtering unit 130 also includes two band pass filters to extract a signal corresponding to the second harmonic component from the first synthesized signal and the second synthesized signal, respectively. Meanwhile, the filtering unit 130 may be composed of two low pass filters to extract signals corresponding to direct current (DC) components from the first synthesized signal and the second synthesized signal, respectively.
결과적으로 신호 검출부(140)는 두 개의 제2고조파 성분 또는 두 개의 직류 성분을 입력받게 된다. 검출대상 신호를 검출하기 위해 신호 검출부(140)는 두 개의 신호 성분의 크기를 기초로 가로축이 sin축이고 세로축이 cos축인 그래프를 작성한다. 제1기준신호와 제2기준신호의 위상차가 90°이기 때문에 sin 및 cos을 각 좌표축으로 하여 각 성분의 크기를 나타낸 직선 그래프를 얻을 수 있으며, 그래프로부터 검출대상 신호의 크기 및 위상을 산출할 수 있다.As a result, the signal detector 140 receives two second harmonic components or two DC components. In order to detect the detection target signal, the signal detector 140 creates a graph in which the horizontal axis is the sin axis and the vertical axis is the cos axis based on the magnitudes of the two signal components. Since the phase difference between the first reference signal and the second reference signal is 90 °, a linear graph showing the magnitude of each component can be obtained using sin and cos as the coordinate axes, and the magnitude and phase of the signal to be detected can be calculated from the graph. have.
도 11에 도시된 것과 같은 미세 신호 검출장치를 사용하면 PLL과 같은 위상 동기화 수단을 사용하지 않고 입력 신호로부터 검출대상 신호를 정확하게 검출할 수 있다.By using the fine signal detection apparatus as shown in Fig. 11, it is possible to accurately detect the detection target signal from the input signal without using a phase synchronization means such as a PLL.
이상에서 본 발명의 바람직한 실시예에 대해 도시하고 설명하였으나, 본 발명은 상술한 특정의 바람직한 실시예에 한정되지 아니하며, 청구범위에서 청구하는 본 발명의 요지를 벗어남이 없이 당해 발명이 속하는 기술분야에서 통상의 지식을 가진 자라면 누구든지 다양한 변형 실시가 가능한 것은 물론이고, 그와 같은 변경은 청구범위 기재의 범위 내에 있게 된다.Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific preferred embodiments described above, and the present invention belongs to the present invention without departing from the gist of the present invention as claimed in the claims. Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (4)

  1. 입력 신호에 포함된 검출대상 신호의 주파수와 동일한 주파수를 가지는 기준 신호를 생성하여 출력하는 기준 신호 생성부;A reference signal generator for generating and outputting a reference signal having the same frequency as that of the detection target signal included in the input signal;
    상기 입력 신호와 상기 기준 신호를 곱하여 합성 신호를 생성하는 주파수 혼합부;A frequency mixer for generating a composite signal by multiplying the input signal by the reference signal;
    상기 합성 신호로부터 상기 검출대상 신호의 주파수에 대한 제2고조파 성분에 해당하는 신호를 추출하는 필터링부; 및A filtering unit configured to extract a signal corresponding to a second harmonic component of the frequency of the detection target signal from the synthesized signal; And
    상기 필터링부에서 출력된 신호로부터 상기 검출대상 신호를 검출하는 신호 검출부;를 포함하는 것을 특징으로 하는 미세 신호 검출장치.And a signal detector for detecting the detection target signal from the signal output from the filtering unit.
  2. 제 1항에 있어서,The method of claim 1,
    상기 필터링부는,The filtering unit,
    상기 합성 신호로부터 직류 성분에 해당하는 신호를 추출하는 저역 통과 필터; 및A low pass filter for extracting a signal corresponding to a direct current component from the synthesized signal; And
    상기 합성 신호로부터 제2고조파 성분에 해당하는 신호를 추출하는 대역 통과 필터;를 포함하며,And a band pass filter for extracting a signal corresponding to a second harmonic component from the synthesized signal.
    상기 신호 검출부는 상기 직류 성분에 해당하는 신호 및 상기 제2고조파 성분에 해당하는 신호 중에서 신호 대 잡음비가 높은 신호로부터 상기 검출대상 신호를 검출하는 것을 특징으로 하는 미세 신호 검출장치.And the signal detector detects the detection target signal from a signal having a high signal-to-noise ratio among a signal corresponding to the DC component and a signal corresponding to the second harmonic component.
  3. 제 1항 또는 제 2항에 있어서,The method according to claim 1 or 2,
    상기 기준 신호 생성부는,The reference signal generator,
    외부로부터 입력받은 제어 전압에 의해 상기 기준 신호를 생성하여 출력하는 전압 제어 발진기;A voltage controlled oscillator generating and outputting the reference signal by a control voltage received from an external device;
    상기 전압 제어 발진기로부터 출력된 상기 기준 신호와 상기 입력 신호를 곱하여 서브 합성 신호를 생성하는 혼합기; 및A mixer for generating a sub-synthesized signal by multiplying the reference signal output from the voltage controlled oscillator and the input signal; And
    상기 서브 합성 신호를 입력받아 상기 전압 제어 발진기를 제어하기 위한 제어 전압을 출력하는 적분기;를 포함하는 것을 특징으로 하는 미세 신호 검출장치.And an integrator that receives the sub-synthesized signal and outputs a control voltage for controlling the voltage controlled oscillator.
  4. 제 1항 또는 제 2항에 있어서,The method according to claim 1 or 2,
    상기 기준 신호 생성부는 상기 입력 신호에 포함된 검출대상 신호의 주파수와 동일한 주파수를 가지는 제1기준신호 및 상기 제1기준신호와 주파수가 동일하며 위상차가 90°인 제2기준신호를 생성하여 출력하고,The reference signal generator generates and outputs a first reference signal having a frequency equal to a frequency of a detection target signal included in the input signal and a second reference signal having a frequency equal to that of the first reference signal and having a phase difference of 90 °. ,
    상기 주파수 혼합부는 상기 제1기준신호 및 상기 제2기준신호에 상기 입력 신호를 각각 곱하여 제1합성신호 및 제2합성신호를 생성하며,The frequency mixer generates a first synthesized signal and a second synthesized signal by multiplying the first reference signal and the second reference signal by the input signal, respectively.
    상기 필터링부는 상기 제1합성신호 및 상기 제2합성신호로부터 각각 상기 검출대상 신호의 제2고조파 성분에 해당하는 신호를 검출하는 것을 특징으로 하는 미세 신호 검출장치.And the filtering unit detects a signal corresponding to a second harmonic component of the signal to be detected, from the first synthesized signal and the second synthesized signal, respectively.
PCT/KR2009/005944 2008-10-16 2009-10-15 Fine signal detector WO2010044626A2 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR20080101647 2008-10-16
KR10-2008-0101647 2008-10-16

Publications (2)

Publication Number Publication Date
WO2010044626A2 true WO2010044626A2 (en) 2010-04-22
WO2010044626A3 WO2010044626A3 (en) 2010-07-22

Family

ID=42107071

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/KR2009/005944 WO2010044626A2 (en) 2008-10-16 2009-10-15 Fine signal detector

Country Status (2)

Country Link
KR (1) KR101046990B1 (en)
WO (1) WO2010044626A2 (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US8912804B2 (en) * 2012-03-09 2014-12-16 Litepoint Corporation Method for identifying self-generated spurious signals

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241923A (en) * 1992-07-23 1993-09-07 Pole/Zero Corporation Transponder control of animal whereabouts
WO2000054420A1 (en) * 1999-03-11 2000-09-14 Mitsubishi Denki Kabushiki Kaisha Radio terminal device
US20030072320A1 (en) * 2001-10-13 2003-04-17 Samsung Electronics Co., Ltd. Direct conversion receiver capable of supporting multiple standard specifications in a mobile communication system
US6707858B1 (en) * 1998-08-25 2004-03-16 Koninklijke Philips Electronics N.V. Low IF receiver

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR920001647Y1 (en) * 1988-12-01 1992-03-06 삼성전자 주식회사 Intermediate frequency change circuit

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5241923A (en) * 1992-07-23 1993-09-07 Pole/Zero Corporation Transponder control of animal whereabouts
US6707858B1 (en) * 1998-08-25 2004-03-16 Koninklijke Philips Electronics N.V. Low IF receiver
WO2000054420A1 (en) * 1999-03-11 2000-09-14 Mitsubishi Denki Kabushiki Kaisha Radio terminal device
US20030072320A1 (en) * 2001-10-13 2003-04-17 Samsung Electronics Co., Ltd. Direct conversion receiver capable of supporting multiple standard specifications in a mobile communication system

Also Published As

Publication number Publication date
WO2010044626A3 (en) 2010-07-22
KR20100042598A (en) 2010-04-26
KR101046990B1 (en) 2011-07-06

Similar Documents

Publication Publication Date Title
US6515276B2 (en) Heterodyne optical spectrum analyzer with provisions for intensity noise subtraction
JP2007532028A (en) Improved RF power control device for RF plasma application
KR100381014B1 (en) Amplitude noise suppression optical intensity modulation apparatus and method using linear optical modulator
EP1574832A3 (en) Optical phase measurement of target
US10656083B2 (en) Chirped laser dispersion spectroscopy sensitivity booster
CN105136175A (en) Phase-sensitive optical time domain reflection system based on self-mixing technology
WO2006004731A3 (en) Systems and methods for chiroptical heterodyning
CN110632388A (en) Frequency mixing-based photoelectric detector frequency response measuring method and device
CN104202101B (en) A kind of shortwave/ultrashort wave instant dynamic spectrum detecting system and method
EP0691758B1 (en) Synchronous detection of optical signals
WO2010044626A2 (en) Fine signal detector
CN106569046B (en) Improved phase noise test device and method based on IF delay line frequency-discrimination method
CN110986912B (en) Signal processing circuit signal interference detection method, storage medium and computer device
BR0308894A (en) Enhanced method and apparatus for tracking a resonant frequency
CN103697877B (en) A kind of light source for high-precision closed-loop optical fiber gyroscope relative intensity noise suppressing method of circuit arrangement
CN109714068A (en) A kind of Compact type broadband channelized receiver based on optical processing technique
CN113405677A (en) High-speed sine gate control single photon detector
CN109856457B (en) Self-adaptive load impedance detection system and method
CN109450551B (en) Multi-octave phase shifting method and device
KR100234418B1 (en) Remote control receiver system
TWI693486B (en) Signal processing device and processing method, alignment system, alignment method and photoetching machine
Cameron et al. Simultaneous Tune and Coupling Feedback during RHIC Run 6
JP2003315393A (en) Impedance measuring device
Alves et al. Real-time motional Stark effect in jet
Gao et al. A single channel input virtual dual-phase lock-in amplifier

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09820776

Country of ref document: EP

Kind code of ref document: A2

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09820776

Country of ref document: EP

Kind code of ref document: A2